New 21.5-inch Retina 4K models expected.
Apple Sends Out Invitations for October 22 Media Event: 'We Still Have a Lot to Cover'
The October 22 date was first reported by AllThingsD earlier this month, and was quickly confirmed by the The Loop's ever-reliable Jim Dalrymple.
The original AllThingsD report claimed that event will focus on the iPad updates, but that OS X Mavericks and the redesigned Mac Pro will also be featured at the event. Apple is due to release a number of other product updates, perhaps most notably new MacBook Pros, but it is apparently still unclear whether those updates will be a part of next week's event.